1. Field of the Invention
The present invention relates to a method and an apparatus for acquiring channel information in a polarization division duplex system that simultaneously performs downlink and uplink data transmission using a same frequency band.
2. Description of Related Art
A current mobile communication system transmits data only in one direction of downlink or uplink for a given frequency band. In such a system, it is possible to accurately acquire channel information without interference by using pilot signals transmitted from each direction.
However, a system that performs bi-directional communications by using a same frequency bandwidth has been developed, like the polarization division duplex system. In cellular mobile communication, bi-directional communications, i.e., duplexing, is performed to simultaneously support a downlink from a base station to a terminal and an uplink from the terminal to the base station. For the bi-directional communications, two methods of frequency-division duplex (FDD), which divides frequency resources, and time-division duplex (TDD), which divides time resources, are used most frequently.
When bi-directional data transmission is simultaneously performed by using a same frequency bandwidth, it is difficult to accurately acquire bidirectional channel information simultaneously without interference.